The present invention relates to an improved contact body for use in a liquid and gas contact apparatus and, in particular, to a contact body formed of alternating corrugated sheets of material.
Contact bodies or packings for gas and liquid contact apparatus such as, for example, cooling towers, have been previously proposed in which the contact body is formed of adjacent corrugated sheets of material. Corrugated sheets are placed adjacent one another with their ridges or crests contacting each other so that channels or passageways are formed between the sheets to provide continuously varying width passages in the sheets which result in the flow direction of the gas and liquid being repeatedly changed during passage through the body. It has been found that contact bodies of this type are highly efficient in operation. One such contact body is shown in U.S. Pat. No. 3,262,682 to Bredberg. This type of cross fluted contact body is commonly used in cooling structures such as shown, for example, in U.S. Pat. No. 5,013,492. This Munters' type pack or contact body has been highly successful in use and generally accepted as a cooling tower medium where fairly large volumes of water are recirculated over it.
In cooling towers in which the Munters', type of contact body has normally been used, a water recirculating system is typically provided. In such systems a certain amount of water is normally bled off from the system in order to keep salts and suspended solids in the water from exceeding certain concentrations due to evaporation. A source of makeup water provides fresh water to makeup for evaporation and bleed-off. However, due to restrictions on water usage, bleed-off levels have been reduced, raising the levels of salts and suspended solids in the recirculating water. As a result, the openings between the sheets become plugged by a combination of hardness salts, biological growth, silt, and other suspended materials in the water. The plugging is exacerbated by the fact that the amplitude heights of the corrugations in the pack are generally made relatively small and oriented angularly in the sheet in order to increase the retention time of the descending water and the cooling efficiency of the contact body. One solution to this problem has been to provide contact bodies with relatively large amplitude heights in their corrugations in order to increase the size of the passageways. However, this results in a reduction of the available contact surface for water and air and considerably less cooling.